This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The clinical relevance in investigating these tissues and interfaces is twofold. Firstly, the challenge in regaining tooth function lost due to periodontal disease lies in encouraging regeneration of critical interfaces that form the tooth attachment apparatus. Effective tissue regeneration requires understanding the union between dissimilar materials such as bone and cementum via the periodontal ligament. In this study we will use TXM and XRF imaging to reveal differences in physical properties in particular structural and mineral variations of healthy and diseased alveolar bone and cementum in humans. The physical properties include observation of degraded collagen fibers, mineral density variations, and mineral and collagen fiber association. Secondly, minimally invasive dentistry seeks repair of carious lesions (tooth decay) as a first step to restoring the damaged tissue. If caries reach dentin, the mineralized collagen-based tissue that forms the bulk of the tooth, decay proceeds at a faster rate and surgical intervention (drill and fill) is required. Due to the complex structure of dentin, it has not been established whether proper mechanical functioning can be restored by remineralization treatments. In this study, using TXM we seek to define structural and property changes associated with dentin remineralization to aid in defining the "quality", or hydrated indentation modulus, of remineralized tissue. TXM images from four identifiable zones of varying mineral content in human dentin carious lesions containing collagen fibrils with interfibrillar apatite nuclei facilitating functional remineralization by regrowth of the apatite crystals will be presented.